Drug dependence (DD) is a chronic disease that requires specialty drug treatment, primary care (PC), and management of related problems. Although patients with DD may be linked with specialty care and PC, their healthcare often remains episodic and fragmented, rather than longitudinal, comprehensive, integrated, and coordinated. As a result, adults with DD often enter addiction treatment later and require acute medical care, rather than entering the system earlier when interventions of lower intensity but longer duration might prevent catastrophes. Chronic disease management (CDM) is a collaborative, longitudinal approach to treatment of certain chronic medical illnesses proven to be more effective than routine care. CDM addresses individual patient and health systems barriers to receipt of needed treatment. However, the effectiveness of CDM for DD has not been tested. The objective of this Addiction Health Evaluation and Disease management (AHEAD) study is to test the effectiveness of CDM for DD in PC. The study will enroll 320 adults with DD who are not in DD treatment, and randomize them to a DD CDM program (the AHEAD Unit) integrated into a real-world PC clinic or to referral to standard PC. All subjects will be assessed regarding DD diagnosis, drug use and problems, readiness to change, health-related quality of life, and medical and drug treatment utilization. Subjects will be evaluated 3, 6, and 12 months later, and health services utilization data will be collected for 2 years from a statewide database. Primary outcomes are illicit drug use, drug-related problems, emergency department visits, and hospitalizations. The application's hypothesis is that compared with standard care, a health services delivery intervention (CDM for DD integrated in PC) will decrease illicit drug use and related problems, and improve healthcare utilization patterns. Improved outcomes using the AHEAD approach would support the adoption of a health services delivery strategy, CDM, to better care for patients with DD.